US1048634A

US1048634A - Grinding-machine.

Info

Publication number: US1048634A
Application number: US54329710A
Authority: US
Inventors: George I Alden
Original assignee: Individual
Current assignee: Individual
Priority date: 1910-02-11
Filing date: 1910-02-11
Publication date: 1912-12-31
Anticipated expiration: 1929-12-31

Description

G. I. ALDEN.

GRINDING MACHINE.

APPLICATION FILED FEB. 11, 1910.

1,048,634. Patented Dec. 31, 1912.

6 SHEETS-SHEET l.

g x ZIIIII. 'Lf 11$ N I 1 N A G. I. ALDEN. I

GRINDING MACHINE.

APPLICATION FILED FEB.11, 1910.

1,048,634. Patented Dec.31,1912.

6 8HEETSSHEBT 2.

G. I. ALDEN. GRINDING MACHINE.

APPLICATION FILED PEB.11, 1910. 1,048,634 Patenbed Dec.31,1912.

G SHEETS-SEEM 3.

G. I. ALDEN.

GRINDING MACHINE.

APPLICATION FILED FEB. 11, 1910.

1,048,634, Patented Dec. 31, 1912.

6 SHEETSSHEET 4.

G. I. ALDEN.

GRINDING MACHINE.

APPLICATION FILED IBB. 11, 1910.

1,048,634. Patented Dec. 31, 1912.

6 SHEETS-611E111 5.

G. I. ALDEN.

GRINDING MACHINE. APYLIOATION TILED rm. 11, 1010.

I Patented Dec. 31, 1912.

6 SHEET$SHEET 6.

I III UNITED "STATES PATENT orrron. v I

GEORGE I. ALDEN, OF WORCESTER, MASSACHUSETTS.

GRINDING-MACHINE.

Specification of Letters Patent. Patented Dec. 31, 1912. Application filed February 11, 1910. Serial No.

To all whom it may concern:

Be it known that I, GEORGE I. ALDEN, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Grinding-Machine, of which the following is a specification. This invention relates particularly to a machine for automatically grinding the two cutting edges of the ordinary blades or knife sections used on mowing machines but obviously it is applicable to the grinding of other edged tools having one or more edges to be ground.

Most of the features of the invention relate more specifically to the grinding of blades having two edges at an angle to each other.

The principal objects of the invention are to provide means whereby the grinding of such thin blades by means of rapidly rotating stones or the like will be prevented from burning or drawing the temper of the edges thereof; to provide racticable and efficient means whereby said lades or knife sections can be fed automatically forward from a magazine holding a pile of them, and a holding means so situated as to hold the blades in proper contact with the rotating stone or the like for grinding one edge; to provide means whereby when the first edge is ground the bladewill be automatically transferred'in a simple and efiicient manner to a second holding means adapted to two grinding positions and hold the blade so that the other edge can be ground preferably by another stone; to provide means whereby the second blade will be thereafter ransferred away from the stone and discharged from the machine; to provide means whereby the above specified means will be operated automatically and in proper order so that while one blade is being fed from its first grinding position to the second, a succeeding blade will be fed into the first grinding position; and means whereby the two blades will be held in the ground on opposite ed es at the same time. Also to pro vide e cient means for clamping the blades in their grinding position at the proper time and for engaging them in such a way as to provide for removing them therefrom in the above described sequence; and to provide practicable and efficient means foropcrating the above mentioned devices preferably from a single source of power.

Further objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which- Figure 1 is a front elevation showing a preferred embodiment of the invention.

Fig. 2 is a rear elevation of a portion of the same on enlarged scale showing the driving belts. Fig. .3 is a plan of the same. Figs. 4

and 5 are enlarged plan views of the knife section manipulating mechanism showing two different positions theref. Fig. 6 is an elevation on enlarged scale ookin in the direction of the arrow of Fig. 3. Fig. 7 is a fragmentary side elevation showing some of the driving mechanism and connected parts. Fig. 8 is an end view of the same with parts in section. Fig. 9 is a horizontal sectional view of the same of the line 99 of Fig. 8 showing parts in plan. Fig. 10 is a detail of the operating cams. Fig. 11 is a section view on the hue 1111 of Fig. 3 showing certain details of the mechanism forholding the blades in position. Fig. 12 is an elevation of the same showingthe parts in another position. Fig. 13 is a bottom plan of the holding plunger. Fig. 14 is a bottom plan of the clamp foot. Fig. 15 is an enlarged plan of one of the blade holding heads, and Fig. 16 is a plan on enlarged scale 'of a mowing machine knife section which can be ground on this machine.

Referring first to Figs. 1 and 2 it will be seen that the invention is shown in a form in which a base 20 supports a tank 21 in which are mounted a pair of grinding wheels 22 and 23 located on parallel shafts 24 but out of al'inement with each other as indicated in Fig. 3. These shafts are shown as adjustable as usual by means of sliding bracket bearings 25 and ratchet levers 26. They are provided With pulleys 27 over which passes a single continuous belt 28 which also passes under an idler pulley 29 so as to drive the two grinding wheels in opposite directions. The power for driving the rest of the mechanism comes from a belt 30, pulley 31 and shaft 32. This shaft is shown as provided with a clutch member 33 adapted to be operated by a lever 34 on the machine to bring it in and out of engagement with a clutch member 35 on a shaft 36. This shaft is shown as provided with a worm and worm wheel' connected with a shaft 37 which, through a sprocket chain 38, drives a shaft 39. This shaft 39 as shown more specifically in Figs. 3 and 7, is provided with a cylindrical cam 40 fixed thereon into the groove of which projects an operating member 41 adjustably connected with a slide 42. This slide is caused obviously to move back and forth in horizontal ways 43, substantially on the level of a table plate'44 for supporting the work. Referring now more especially to Figs. 4 and 5 it will be seen that on this slide is a plunger 45 having a longitudinal projecting end 46 and a front wall 47 which makes an angle with the direction of motion of the plunger. Located over the path of thls slanting wall on the plunger is a magazine 48 having such cross section that it will receive the unsharpened blades or knife sections piled one upon another. This magazine has .a passage therethrough at the bot- 'tom through which the flat plunger 45 is theleft of Figs. 4

adapted to pass. reciprocation of this plunger operates to force the bottom blade B out of the magazine along a wall 49 to the position indicated'at and 5. It will be noticed that the blade. B is directly over the grinding wheel 22 which projects slightly above the edge of the table plate. which the blade is held in while it is being ground will be described hereinafter. As the blade is fed forward from its original position into the position B in Fig. 4, it will be noted that it does not The Way in this position follow exactly the motion of the plunger but is kept against the wall 49 by a spring 50 located on the plunger. Pivotally mounted on a stationary vertlcal stud 51 isan arm 52. This arm is operated by a link 53 connected with the slide 42. Also pivotally mounted on a stationary stud on a bracket 54 is a second arm 55 operated by a link 56 in a similar way. These arms are rovided with heads 57 and 58 respectivefy. The head 58 is shown in Fig. 1 5 and the other head is of substantially the same construction but left-handed. It will be suflicient to describe the one shown in Fig. 15.- In this case the head is adjustably mounted on the arm by means of bolts 59 extendin through slots in the arm. On this head is a pivot 60 on which is swingingly mounted a finger 61 having a flat edge adapted to engage the rear surface of the blade. ,This finger is adapted to swin slightly on the pivot so as to permit a slig tplay of the blade. It is adjusted by a screw 62 and yieldingly held in position for engaging the blade by a spring 63. On the head also is a fixed pin 64 which operates to engage in one of the perforations b on the blade to transfer the latter as .the arm moves. As the slide 42 It will be seen that the moves from the position shown in Fig. 4 after a blade has been ground on one side, to the position shown in Fi 5, the pin 64 engaging in one of the per orations in the blade and the finger engaging the back, the arm 52 will swing through the arc of a circledesigned as substantially equal to the angle between the two edges of the blade B until it comes into the position shown in Fig. 5. The pin meantime travels in a curved slot 65 in the table plate. This swings the blade around into proper position to be ground on the stone 23. It will be noticed that at the same time another blade B has been brought into the position of the first blade as clearly shown in Now as the slide 42 moves back the parts will come back to the position shown in Fig. 4 and the pin 64 of the arm 52 will enter the perforation in the blade B (in a way to be described hereinafter) and the same will be positioned ready for grinding on the stone 22. On the next forward motion of the slide 42 while the blade B is moved;

into its second grinding position the arm 55 will perform its function. 1 It will be noted Fig. 5.

that with the parts in the position shown in I Fig. 4 this arm 55 is in position. for its pin 64 to engage in the other perforation b in the blade which happens to be in its second grinding position, while its finger 61 is in position to engage blade. Now as the slide moves forward, the arm 55 swings forward to the position shown in Fig. 5 and carries the blade B with it, the pin moving in a curved slot 66 in the table plate. This shows the motions of the blade and it now remains to describe how the, pins are engaged in the perforations b andhow the blade is clamped so that it-can be ground. On the shaft 37 as shown in Fig. 7 particularly, are two

cams

70 and 71 called respectively the table cam and locking cam.. On the table cam rests a roll 72 which is rotatably mounted on a stud fixed to a table lift arm 73; consequently, the table cam lifts this arm. 'On this arm is mounted a vertical rod 74 and a vertical hollow rod 75. These two rods support the table plate 44 and motion is imparted thereto to raise and drop it slightly once during each revolution of the shaft 37. This moves the blades toward and from the grinding wheels. @A spring 76 is em loyed to assist the downward motion .of t e table and to yieldingly hold the blades against the wheels. The locking cam 71 operates a roll 79 mounted on a-clamp lift arm 80 which is secured to a rod 82 which passes through the hollow rod 75. A spring 81 is shown for the same purpose as the spring 76. On this rod 82 is mounted a bracket 83 provided with an operatin wedge 84 at the end thereof. This operating wedge is adapted to be moved upwardly by the motion the back edge of that of the rod -13 82 between the ends of a pair of toggle lever in detail in Fig. 11,Eguided in supports 93 on the table plate. ch of these plungers is providedat the bottom with a clamp foot 94 having blade WhlCh is supported by the table plate. This clam foot is removably secured to .Zhe bottom 0 the plunger. The operation-of this part of the device will now be understood. Briefly described, the operation is as follows :Starting, for instance, from the position in which the table is u and the blades have just been "ground, t e clamps are first released and the ground blades are moved forward 'by the motion of the slide and arms as heretofore described so that a new blade is brought into the position B, the blade in that position is moved into the position B, and the blade in the latter position is discharged from the ma- (shine. The clamps are then brought into operation and the table "drops rapidly at first and then more gradually to bring the parts'into'the position shown in Fig. 5' in I which the blades are in position for grinding on the stones. This also releases the blades fromthe pins of the arms 52 and 55.,

The blades are held by the clamps at this time. During the grinding operation the slide 42 moves back to the position shown n Fig. 4, taking the arms and plunger with it. The finger pieces 61, being yieldingly mounted, slide over the blades, which are held by the clamps, until the finger-pieces come to the back of the blades so that the two arms are in position with the pins over the perforation'b. The table then rises to engage-the pins in the blades and remove the blades from the stones. The initial rapid: descent; of the table is to save time during the grinding of the corners. When the stone reaches a point where the cut is wider the speed of the table is reduced. This also allows a better finish. This mot1on of course is governed by the shape of. the cam 70. The roll 72 is on the low part of the cam only during grindin and from the time the parts first reach t e position shown in Fig. 5 until they reach that shown in Fig. 3, z. e., while the slide is moving back. The clamps are brought down by the cam 71- just before the tab e descends and they rise just after the table rises. Therefore the high part of the cam 71 is at the same side as the low part of the cam 70 but extends beyond it at both ends.

a three point contact with the,

I have found that the ordinary applica tion of water to thin cutter blanks of this description is not sufficient ordinarily to prevent them from being burned or the temper from being drawn when ground automatically by artificial wheels on two edges in quick succession without the attention of an operator. culty I have provided means whereby the burning or temper drawing is effectively prevented in a very simple and" convenient manner. For this purpose a pump 100 of any desired character is provided drawing water from anysource, preferably from a settling tank 101, and supplying it to a pres-v sure tank 102 under considerable pressure. I have found for example that a pressure of 100 to 150 pounds per square inch is ver suitable for this purpose. From this tan the water is forced through a pipe 103 into a pair of distributing pipes-l04 through a valve 105. From each. of the pipes 104 it passes by means of connections 106 into a chamber 108 in each of the plungers 92. The supports for the plungers are provided with elongated passages 109 for receiving the connections 106 in all positions of the plungers. The bottom of each plunger is provided with a long narrow slot 110 by w .the water issues in direct contact with the blanks or blades along a line a little back ich { from the edge during the entire time durin which the blank or blade is being groun In fact the cooling water under this heavy pressureis discharged on the blade through- ;out the time while it is in osition so that in :addition to cooling the b ade is keeps the other parts of the mechanism cool. I have found in practice that by providing a flow "of water under high pressure the heat is carried ofl with such rapidity that even fwith thin blades of the particular temper required for mowing machines no appreci- .able burnin or temper drawing takes place. The water 1s discharged over the blades on the surface of the stones and issues from an Qopening 111 in the casing 21. It then passes into the settling tank where it is strained 'and settled so that the particles removed from the stones are left in the bottom and the clearwater is used over and over. This matter is not claimed herein, however, as it :forms the subject matter of my co-pending application Serial No. 543,298, filed Feb. 11, 1910. The drawings also show an ordlnary {form of mechanism 112 for grinding off the stone accurately while in position, a lever 113 being employed for o eratin it. These parts are illustrated as 0 an or inary well, known construction and do not form part {of the present invention.

The operation of the machine has been described in connection with the description of the mechanism shown in the drawings.

1 While I have illustrated and described a preferred embodiment of the invention and shown it as applied to the grinding of mowing machine knife sections or blades, I-am aware that many modifications can be made therein and that it can be applied to the grinding of other edged implements and tools without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be limited to the exact form of the invention described nor to the exact use of the invention referred to but What I do c'laimis 1. In a grinding machine, the combination of a grinding wheel, a. magazine constructed and adapted to hold articles to. be ground in a pile therein, means for positively removing the articles edg'ewise one at a time transversely from the magazine, and means for holding them in position to be ground on the wheel.

2. In a grinding machine, the combination of a magazine for articles to be ground,

a plunger passing below said magazine,-

means for reciprocating said plunger to push an article out of they magazine into position to be ground, and means for grinding said article.

I 3. In a grinding machine, the combination of a magazine for articles to be ground, a plunger passing below said magazine,

means for reciprocating said plunger to push an article out of the magazine into position to .be ground on one side, and means for thereafter transferring the article into position to be ground on the other side.

4. In a grinding machine, the combination of a magazine for articles to be ground,

. a plunger passing below said magazine, a

shaft, means connected with said shaft for reciprocating said plunger to push an article out of the magazine into position to be ground on one side, and means operated by said shaft for thereafter transferring the "article into position to be ground on the other side; a v

5. In agrinding machine, the combination .of a magazine adapted to support apile offlat articles therein, two grinding stones, means for moving an article edgewise from the magazine into position to be ground on one edge by one stone, and means for thepeafter moving the article edgewise into positionto be ground on the opposite edge by the other stone.

6. In a grinding machine the combination of a magazine for articles to be ground, a

' plurality of grinding stones 'on the same side of the magazine, means for moving the artif cle from the magazine into position to be ground on one side by the nearest stone, means for thereafter moving the article into position to be ground on another. stone, and means for thereafter removing the article from the machine.

7. In a grinding machine, the combination of a table plate,means for .movlng an article to be ground into grinding position thereon, means for grinding one edge of the article, means for then moving the article into a second grinding posit-ion on the table plate, and means for grinding another edge of the article at an angle to the first edge in its second position.

8. In a grindingmachine, the combination I of a table plate, means for'moving an article to be ground into grindin thereon, means for grinding t e article, means for then moving the article along in the same general direction into a second grinding position on the table plate, means for grinding the article in its secondposition, and means for thereafter removing the position first article from its second grinding pom) tion.

9. In a grinding machine, the combination of means for moving a flat article in a plane into grinding position, meansifor grinding the article, means for then moving the article in the same plane into a second grinding positioh, and means for grinding the article in its second position-while another article is being ground in the first grinding position.

10. In a grinding machine, the combination'of a stationary table plate, means for movingan article to be ground on the table plate, means for grinding the article while in position thereon, means for moving the article along the table plate into a second position, means for grinding a different edge Y of the article while in the second position,

and means for thereafter removing the artithereof, means for' rotating said grinding stones in opposite directions, means feeding an article to be ground to a position on the table plate in which its edge projects into contact with one of the stones, and

means for thereafter feeding said article to a position in which its opposite edge projects into engagement with the other stone.

12. In a grinding machine, the combination of .a table plate, a pair of grinding stones under said plate, each projecting slightly above the plate at opposite edges thereof and out of alinement with .each. other, means for rotating said stones in opposite directions, and means. for moving an article to be ground from position into engagement with one stone to a position in engagement with the other stone.

13. In a grinding machine, the combinafor tion of a table plate, a slide movable adjacent to said table plate, a plunger on the sl1de.adapted to engage an article to be ground and move it intogrinding position,

an arm pivotally mounted with respect to'f:

saidtable plate, and means whereby when the slide moves forward, said arm will move said article along the table plate into a second position.

14. In a grinding machine, the combination of a magazine for articles to be ground a plunger movable through said magazine, said plunger having a longitudinal projection on one edge beyond the magazine, and a spring on said plunger near said projection for engaging an article moved by the plunger, and holding it in proper position, said plunger having a forward surface for engaging the article to be ground located at an angle to said projection.

15. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, arms mounted on the tablepl ate for moving an article to be ground, means connected with the slide for operating said arms, a plunger fixedly mounted on the slide and moving the article to be ground in position to be engaged by said arms, said plunger having a longitudinal projection at one end thereof, and a spring on said plunger near said' projection for engaging the article to be 'moved and holding it away from said projection.

16. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, means movable with said slide for advancing an article to be ground into grinding position, and means simultaneously movable with said slide for removing an article from said grinding position and advancing it to another posit-ion on the table plate when the slide moved forward.

17. In a grinding machine, the combination of a table late, a slide movable adja cent thereto, a link pivotally connected with said slide, an arm plvoted on said table plate and connected with said link, means on said arm for engaging the edge of an article to be ground comprising a finger piece, and means for adjusting said finger piece along the arm.

18. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, two links pivotally connected with said slide, two arms each pivoted to said table -plate, the point of pivotal connection of the table with one arm being at one side of the path of said slide, and that of the other arm being at the other side, each arm projecting inwardly from its point of pivotal connection with the table plate, each of said links being connected with one of the arms, whereby as the slide moves both of the arms will be swung on their pivots, the paths of movement of the ends of the arms intersecting each other, and means on each arm for engaging an article to be ground and moving it along with the arm as it swings.

19. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, means movable with said slide for advancing an article to be ground'into grinding position, and means simultaneously movable with said slide for removing an article from said grinding position and advancing it to another posit-ion on the table plate when the slide moves forward, and means movable with said slide for advancing an article from said second position and discharging it from the machine when the slide moves forward.

20. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, a linkpivotally connected with said slide, an arm pivoted on said table plate and connected with said link, and means on said arm for engaging the edge of an article to be ground.

21.. In a grinding machine, the combination of a table plate, a slide movable adjacent thcreto, a link pivotally connected with said slide, an arm pivoted on said table plate and connected with said link means on said arm for engaging the edge of an article to be ground, said means comprising a finger piece pivotally mounted on the arm to swing on a pivot parallel with the pivot about which the arm swings.

22. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, a link pivotally connected with said slide, an arm pivoted on said table plate and connected with said link, means on said arm for engaging the edge of an article to be ground, and means on the arm for positively engaging a definite portion of the article to be ground, whereby when the arm moves on its pivot said article will be dragged along the table plate with'it.

23. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, a link pivotally connected with said slide, an arm pivoted on said table plate and connected with said link, means on said arm for engaging the edge of an article to be ground, and a pin projecting from said arm for engaging in a perforation in the article to be ground.

24. In a grinding machine, the combination of a table plate, a pair of grinding stones under said plate, each projecting. slightly above the plate at opposite edges thereof and out of alinement with each other, means for rotating said stones in opposite directions, means for moving an article to be ground from position into engagementwith one stone to a position in engagement with the other stone, said means comprising a pin adapted to pass through a perforation in the article, means for moving the pin, and a movable pin for engaging in a perforation in the article while in second position and transferring it from the table plate.

. said first named pin as ittransfers the 25. In. a grinding machine, the combination of a table plate, a pair of grinding stones under said plate, out of alinement with each other, a pin adapted to pass through a perforation in the article, means for moving the pin, and a movable pin for article to be ground, and a second groove for receiving the second pin as it discharges the article from the table plate.

26. In agrinding machine, the combina tion of a tableplate, a pin adapted to pass through a perforation in the article, means for moving the pin, and a movable pin for engaging in a perforation in the article while in a second position and transferring it from the table plate, and means for raising the table whereby the articles resting thereon will be brought up into such position that the pins will project into the perforations in the articles, and whereby when the table plate is lowered the articles will be freed from the pins. 1

27. In a grinding machine, the combination of a table plate, a slide movable adjacent thereto, a link pivot-ally connected with said slide, an arm pivoted on said table plate and connected with said link, means on said arm for engaging the edge of an article to be ground, means for raising said table plate to bring the article resting thereon into engagement with said means, and for lowering the table plate to disengage it therefrom after the article has been transferred to the second position.

28. In a grinding machine, the combination of a table plate, means for moving an article to be ground over the surface of the table plate into first grinding position, an arm located over the table plate, means for ralslng the table plate to bring the said artlcle into engagement with said arm, an means for thereafter moving the arm to transfer the article to another position on the table plate.

29. In a grinding machine, the combination of a table plate, means for moving an article to be ground over the surface of the table plate into first grinding position, an arm located over the table plate, means for raising the tableplate to bring the said article into engagement with said arm, means for thereafter moving the arm to transfer the article to another position on the table plate, means for then lowering the table plate to disengage it from the arm,

and means for thereafter engaging the article and discharging it from the table plate.

30. In a grinding machinathe combinenon of a table plate,

tion of a table plate,

d the table plate, a clamping table plate, and

means for moving an article to be ground over the surface of the table plate into first grinding position, an. arm located over the table plate, means for raising the table plate to bring the said article into engagement with said arm, means for thereafter moving the arm to transfer the article to another position on the table plate, means for lowering the table plate to release the article from said arm, means for moving the arm away, another arm, and means whereby when the table plate is again raised the article will be engaged by said other arm and transferred from the table plate.

31. In a grinding machine/the combination of a table plate, means for moving an article to be ground over the surface of the table plate into first grindingposition, an arm located over the table plate, means for raising the table plate to bring the said article into engagement with said arm, means for thereafter moving .the arm to transferrthe article to another position on the-table plate, and means for then clamping said article on the table plate.

.32. In a grinding machine, the combinameans for moving an article to be ground over the surface of the table plate into first grinding position, an arm located over the table plate, means for raising the table plate to bring the said article into engagement with said arm, means for thereafter moving the arm to transfer the article to another position on the table plate, means for then clamping said article on the table plate, means whereby after the article is ground the clamping means will be released, means for moving the arm to transfer the article from second position, and means whereby the article will be clamped in said second position.

33. In a grinding machine, the combination of a shaft, a'table cam and a locking cam thereon, a table plate, means operated by said table cam for raising and lowering device over the ing cam for operating said clamping device after the table plate has been raised.

34:. In a grinding machine, the combination of a table cam and a locking cam, a table plate, means operated by said table cam for raising and lowering the table plate, a clamping device, and means operated by the locking cam for operating said clamping device, and-for releasing the clamping device while the table is raised.

35. In a grinding machine, the combination of a shaft, a cam thereon, a table lift arm having a roller resting on said cam, said arm projecting from the roller in opposite directions, two rods projecting upwardly from said table lift arm, and a table plate supported by said rods.

means operated by the lock- 36. In a grinding machine, the combination of a shaft, a cam thereon, a table lift arm having a roller resting on said cam, said arm projecting from the roller in opposite directions, two rods projecting upwardly from said table lift arm, a table plate supported by said rods, one of said rods being hollow, a third rod passing through said hollow rod, means for operating the third rod, and means connected therewith for clamping articles on the table plate.

.37. In a grinding machine, the combination of a shaft, a cam thereon, a table lift arm having a roller resting on said cam, said arm projecting from the roller in opposite directions, two rods projecting upwardly from said table lift arm, a table plate supported by said rods, another cam on said shaft, a clamp over the table, and means operated by the second cam for moving said clamp into and out of operative position.

38. In a grinding machine, the combination of a shaft, a cam thereon, a table lift arm having a roller resting on said cam, said arm projecting from the roller in opposite directions, two rods projecting upwardly from said table lift arm, a table plate supported by said rods, another cam on said shaft, a clamp over the table, means operated by the second cam for moving said clamp into and out of operative position, resilient means for assisting the table plate to move downwardly, and resilient means for moving the clamp out of operative position.

39. In a grinding machine,the combination of a supporting table for the work, means for clamping the work thereon, a grinding member located adjacent to said table, and means for moving the table transversely toward the grinding member when the Work is clamped upon it.

40. In a grinding machine, the combination of a supporting table for the work, a grinding member located under it, means for moving the table downwardly toward the grinding member, with an initially rapid motion and a slower motion at the end of the stroke and means for holding the work clamped on the ,table while being moved down.

41. In a grinding machine, the combination of a supporting table for the work, a

shaft, means connected with said shaft for moving the work into position on the table, means for clamping the work on the table, and means operated by said shaft for lowering the table to bring the work into position for grinding.

42. In a grinding machine, the combination of a supporting table for the Work, means for moving the work into position on the table, means for clamping the work on the table, and means for lowering the table to bring the work into position for grinding with an initially rapid motion and a slower motion at the end of the stroke.

43. In a grinding machine, the combination of a supporting table for the work, means" for moving the work into position on the table, means for clamping the work on the table, means for lowering the table to bring the work into position for grinding and for thereafter raising the table, and means for then removing the work from grinding position.

44. In a grinding machine, the combination of a table plate for supporting the articles to be ground, means for moving the articles along said plate from one grinding position to another, means for simultaneously clamping the articles in both grinding positions, said last named means comprising a pair of plungers, each having a clamp-foot thereon, a movable member, and a pair of sets of levers adapted to be engaged simultaneously by the movable member for operating the plungers.

45. In a grinding machine, the combination of a table plate for supporting the articles to be ground, means for moving said articles from one grinding position to another grinding position on said table plate, a pair of plungers, one located over each of said grinding positions, two sets of toggle levers, one connected with each plunger, and a reciprocable wedge-shaped member adapted to engage said toggle levers and simultaneously operate them to depress the plungers.

46. In a grinding machine, the combination of a table plate for supporting the work to be ground, means for moving the said table plate vertically, a stationary support adjacent to the table plate, a plunger mounted to move vertically on said support, and to engage the top of the table plate to hold the work thereon, a toggle lever connected with said support and with the plunger, and a movable member adapted to operate the toggle lever to depress the plunger while the table is raised.

47. In a grinding machine, the combination of means for supporting the articles to be ground, a clamping plunger for clamping the articles on said means, said plunger having a clamping foot removably mounted thereon at the bottom and having a plane surface provided with a plurality of points projecting therefrom for engaging the work.

48. In a grinding machine, the combination of a table plate for supporting the articles to be ground, means for moving the articles along said plate from one grinding position to another, and means for simultaneously clamping the articles in 'both grinding positions.

49. In a grinding machine, the combination of a table plate, two grinding stones out of alinement, but located parallel to each other, means for feeding an article to be ground to a position on the table plate in which its edge projects into contact with one of the stones, and means for thereafter feeding said article to a position in which its opposite edge projects into engagement with the other stone.

50. In a grinding machine, the combination of a table plate, two grinding stones located below the plate at opposite edges thereof, means for feeding an article to be gronnd to a position on the table plate in which its edge projects into contact ,with one of the stones, and means for thereafter 15 feeding said article to a position in which its opposite edge projects into engagement with the other stone.

In testimony whereof I have hereunto set my hand, in the presence'of two subscribing 20 witnesses.

, Gnonen r. ALDEN. Witnesses:

\ G. 0. SMITH,

A. J. Dorm).